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62627bec8a
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John Stultz 62627bec8a x86: tsc: Fix calibration refinement conditionals to avoid divide by zero 
Konrad Wilk reported that the new delayed calibration crashes with a
divide by zero on Xen. The reason is that Xen sets the pmtimer
address, but reading from it returns 0xffffff. That results in the
ref_start and ref_stop value being the same, so the delta is zero
which causes the divide by zero later in the calculation.

The conditional (!hpet && !ref_start && !ref_stop) which sanity checks
the calibration reference values doesn't really make sense. If the
refs are null, but hpet is on, we still want to break out.

The div by zero would be possible to trigger by chance if both reads
from the hardware provided the exact same value (due to hardware
wrapping).

So checking if both the ref values are the same should handle if we
don't have hardware (both null) or if they are the same value (either by
invalid hardware, or by chance), avoiding the div by zero issue.

[ tglx: Applied the same fix to native_calibrate_tsc() where this
  	check was copied from ]

Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: John Stultz <johnstul@us.ibm.com>
LKML-Reference: <1295024788-15619-1-git-send-email-johnstul@us.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-01-14 18:28:01 +01:00
..
acpi Merge branch 'linus' into x86/apic-cleanups 2011-01-07 14:14:15 +01:00
apic x86, UV: Fix APICID shift for Westmere processors 2011-01-11 12:44:45 +01:00
cpu Merge branches 'x86-alternatives-for-linus', 'x86-fpu-for-linus', 'x86-hwmon-for-linus', 'x86-paravirt-for-linus', 'core-locking-for-linus' and 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2011-01-06 11:11:50 -08:00
.gitignore
alternative.c Merge branches 'x86-alternatives-for-linus', 'x86-fpu-for-linus', 'x86-hwmon-for-linus', 'x86-paravirt-for-linus', 'core-locking-for-linus' and 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2011-01-06 11:11:50 -08:00
amd_iommu_init.c Merge branch 'x86-iommu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-10-21 14:23:48 -07:00
amd_iommu.c x86/amd-iommu: Update copyright headers 2010-10-13 11:13:21 +02:00
amd_nb.c x86: Use PCI method for enabling AMD extended config space before MSR method 2011-01-11 12:43:41 +01:00
apb_timer.c x86, apbt: Setup affinity for apb timers acting as per-cpu timer 2010-12-06 15:58:26 +01:00
aperture_64.c x86: Use PCI method for enabling AMD extended config space before MSR method 2011-01-11 12:43:41 +01:00
apm_32.c Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2010-10-24 13:41:39 -07:00
asm-offsets_32.c x86, asm: Fix CFI macro invocations to deal with shortcomings in gas 2010-10-19 14:28:02 -07:00
asm-offsets_64.c
asm-offsets.c
audit_64.c
bootflag.c
check.c x86: Use memblock to replace early_res 2010-08-27 11:12:29 -07:00
cpuid.c BKL: remove extraneous #include <smp_lock.h> 2010-11-17 08:59:32 -08:00
crash_dump_32.c mm: stack based kmap_atomic() 2010-10-26 16:52:08 -07:00
crash_dump_64.c mm, x86: Saving vmcore with non-lazy freeing of vmas 2010-09-17 09:11:56 +02:00
crash.c x86, UV: Make kdump avoid stack dumps 2010-07-21 11:33:27 -07:00
doublefault_32.c
dumpstack_32.c x86: Eliminate bp argument from the stack tracing routines 2010-11-18 14:37:34 +01:00
dumpstack_64.c x86: Eliminate bp argument from the stack tracing routines 2010-11-18 14:37:34 +01:00
dumpstack.c x86: Eliminate bp argument from the stack tracing routines 2010-11-18 14:37:34 +01:00
e820.c x86, memblock: Use memblock_memory_size()/memblock_free_memory_size() to get correct dma_reserve 2010-08-27 11:13:54 -07:00
early_printk.c x86, earlyprintk: Move mrst early console to platform/ and fix a typo 2010-12-06 20:52:04 +01:00
early-quirks.c Merge branch 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-10-21 13:18:06 -07:00
entry_32.S x86, asm: Fix binutils 2.15 build failure 2010-11-18 09:25:11 +01:00
entry_64.S x86/kprobes: Prevent kprobes to probe on save_args() 2010-11-18 13:40:19 +01:00
ftrace.c x86: Add RO/NX protection for loadable kernel modules 2010-11-18 13:32:56 +01:00
head32.c x86: Add CE4100 platform support 2010-11-12 00:45:41 +01:00
head64.c x86-64: Only set max_pfn_mapped to 512 MiB if we enter via head_64.S 2010-10-14 09:06:49 +02:00
head_32.S Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2011-01-06 11:12:17 -08:00
head_64.S x86-64: Simplify loading initial_gs 2010-07-21 21:23:51 -07:00
head.c x86: Use memblock to replace early_res 2010-08-27 11:12:29 -07:00
hpet.c x86: HPET: Chose a paranoid safe value for the ETIME check 2010-12-13 13:42:44 +01:00
hw_breakpoint.c x86: Ignore trap bits on single step exceptions 2010-11-12 14:51:01 +01:00
i386_ksyms_32.c
i387.c Merge branch 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-10-21 13:34:32 -07:00
i8237.c
i8253.c
i8259.c x86: i8259: Convert to new irq_chip functions 2010-10-12 16:53:36 +02:00
init_task.c
io_delay.c
ioport.c
irq_32.c x86-32: Restore irq stacks NUMA-aware allocations 2010-10-29 08:17:07 +02:00
irq_64.c
irq_work.c irq_work: Add generic hardirq context callbacks 2010-10-18 19:58:50 +02:00
irq.c Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-10-21 14:11:46 -07:00
irqinit.c Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-10-21 14:11:46 -07:00
jump_label.c jump label: x86 support 2010-09-22 16:33:03 -04:00
kdebugfs.c llseek: automatically add .llseek fop 2010-10-15 15:53:27 +02:00
kgdb.c kgdb,x86: fix regression in detach handling 2010-11-17 13:54:57 -06:00
kprobes.c kprobes: Use text_poke_smp_batch for unoptimizing 2010-12-06 17:59:32 +01:00
kvm.c
kvmclock.c KVM guest: Move a printk that's using the clock before it's ready 2010-10-24 10:53:06 +02:00
ldt.c
machine_kexec_32.c
machine_kexec_64.c x86, cleanups: Use clear_page/copy_page rather than memset/memcpy 2010-09-22 15:36:49 -07:00
Makefile Merge branch 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2011-01-06 11:06:31 -08:00
mca_32.c
microcode_amd.c Merge branch 'x86-microcode-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2011-01-06 11:06:09 -08:00
microcode_core.c Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2010-10-24 13:41:39 -07:00
microcode_intel.c x86/microcode: Fix double vfree() and remove redundant pointer checks before vfree() 2010-12-27 14:33:30 +01:00
mmconf-fam10h_64.c x86-64: Fix and clean up AMD Fam10 MMCONF enabling 2010-11-18 13:41:35 +01:00
module.c Merge commit 'v2.6.36-rc7' into perf/core 2010-10-08 10:46:27 +02:00
mpparse.c x86: Further simplify mp_irq info handling 2010-12-09 21:52:06 +01:00
msr.c BKL: remove extraneous #include <smp_lock.h> 2010-11-17 08:59:32 -08:00
paravirt_patch_32.c
paravirt_patch_64.c
paravirt-spinlocks.c
paravirt.c x86, paravirt: Remove alloc_pmd_clone hook, only used by VMI 2010-08-23 17:09:44 -07:00
pci-calgary_64.c x86, calgary: Make Calgary IOMMU use IOMMU_INIT_* macros. 2010-08-26 15:14:15 -07:00
pci-dma.c x86, iommu: Utilize the IOMMU_INIT macros functionality. 2010-08-26 15:14:52 -07:00
pci-gart_64.c x86, amd-nb: Cleanup AMD northbridge caching code 2010-11-18 15:53:05 +01:00
pci-iommu_table.c x86, iommu: Add proper dependency sort routine (and sanity check). 2010-08-26 15:13:19 -07:00
pci-nommu.c
pci-swiotlb.c x86, swiotlb: Make SWIOTLB use IOMMU_INIT_* macros. 2010-08-26 15:13:37 -07:00
pcspeaker.c
probe_roms_32.c
process_32.c perf: Clean up power events by introducing new, more generic ones 2011-01-04 08:16:54 +01:00
process_64.c perf: Clean up power events by introducing new, more generic ones 2011-01-04 08:16:54 +01:00
process.c perf: Clean up power events by introducing new, more generic ones 2011-01-04 08:16:54 +01:00
ptrace.c ptrace: cleanup arch_ptrace() on x86 2010-10-27 18:03:10 -07:00
pvclock.c x86/pvclock: Zero last_value on resume 2010-11-28 09:33:20 +01:00
quirks.c x86: HPET force enable for CX700 / VIA Epia LT 2010-09-15 16:27:04 +02:00
reboot_fixups_32.c x86: Ce4100: Add reboot_fixup() for CE4100 2010-11-12 00:45:41 +01:00
reboot.c Merge branch 'linus' into x86/urgent 2010-10-25 19:38:52 +02:00
relocate_kernel_32.S
relocate_kernel_64.S
resource.c x86: avoid high BIOS area when allocating address space 2010-12-17 10:01:30 -08:00
rtc.c
setup_percpu.c Merge branch 'core-memblock-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-10-21 18:52:11 -07:00
setup.c Merge branch 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2011-01-06 10:51:36 -08:00
signal.c
smp.c x86, kexec: Make sure to stop all CPUs before exiting the kernel 2010-10-21 13:30:44 -07:00
smpboot.c x86: Fix sparse non-ANSI function warnings in smpboot.c 2011-01-09 10:15:19 +01:00
stacktrace.c x86: Eliminate bp argument from the stack tracing routines 2010-11-18 14:37:34 +01:00
step.c
sys_i386_32.c i386: Make kernel_execve() suitable for stack unwinding 2010-09-03 08:16:02 +02:00
sys_x86_64.c
syscall_64.c
syscall_table_32.S x86: fix up system call numbering nit 2010-08-10 15:35:10 -07:00
tboot.c Merge branch 'kvm-updates/2.6.35' of git://git.kernel.org/pub/scm/virt/kvm/kvm 2010-05-21 17:16:21 -07:00
tce_64.c
test_nx.c
test_rodata.c
time.c x86, nmi_watchdog: Remove all stub function calls from old nmi_watchdog 2010-11-18 09:08:23 +01:00
tls.c
tls.h
topology.c
trampoline_32.S
trampoline_64.S x86, cpu: Rename verify_cpu_64.S to verify_cpu.S 2010-11-10 15:42:42 -08:00
trampoline.c Merge branch 'x86-trampoline-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-10-22 20:37:50 -07:00
traps.c x86, NMI: Add touch_nmi_watchdog to io_check_error delay 2011-01-05 14:22:58 +01:00
tsc_sync.c
tsc.c x86: tsc: Fix calibration refinement conditionals to avoid divide by zero 2011-01-14 18:28:01 +01:00
verify_cpu.S x86: Fix included-by file reference comments 2010-11-18 09:58:54 +01:00
vm86_32.c x86, vm86: Fix preemption bug for int1 debug and int3 breakpoint handlers. 2010-09-23 11:07:49 -07:00
vmlinux.lds.S x86: Add NX protection for kernel data 2010-11-18 12:52:04 +01:00
vsmp_64.c
vsyscall_64.c timkeeping: Fix update_vsyscall to provide wall_to_monotonic offset 2010-07-27 12:40:54 +02:00
x86_init.c x86: Introduce x86_msi_ops 2010-10-18 10:49:34 -04:00
x8664_ksyms_64.c
xsave.c x86, xsave: Use alloc_bootmem_align() instead of alloc_bootmem() 2010-12-13 16:13:11 -08:00